The potential advantages of using wide-range parallel energy detection of charged particles to speed up spectrometer data acquisition times are well known, and documented in the following citations: [1]. M. Jacka, M. Kirk, M. M. El Gomati, M. Prutton, Rev. Sci. Instrum. 70 (5) (1999) 2282-2287, [2]. M. Jacka, A. Kale, N. Traitler, Rev. Sci. Instrum. 74(10) (2003) 4298-4300, and [3]. M. Jacka, J. Electron. Spectrosc. Relat. Phenom. 114-116 (2001) 277-282. One class of parallel analyzer designs is based upon the Hyperbolic Field Analyser (HFA), which has also been developed into an Auger Electron Spectroscopy (AES) attachment for Scanning Electron Microscopes (SEMs) to be used in combination with a low voltage Argon ion source. In particular, the entire Auger electron spectrum from the HFA may be captured within one/two seconds after a surface of a specimen (under examination) has been cleaned by the ion gun, before any appreciable hydrocarbon contamination is allowed to form. Also, use of the HFA opens up a possibility of performing AES at high vacuum pressures, instead of at Ultra High Vacuum (UHV) conditions which is typically done. Thus, performing AES with SEMs allows mapping of elemental information on a nano-scale to be feasible.
One problem with analysers based on existing HFA design is that they suffer from relatively low transmittance. Even with improvements, the overall transmittance is still typically around 100 times smaller than that of the Cylindrical Mirror Analyser (CMA) at comparable energy resolutions. The relatively low transmittance is mainly due to the HFA designs being characterised by first-order focusing properties on the detector plane, limiting the angular spread in the plane of deflection to fairly small values, typically less than ±1.2°. Further, conventional HFA designs are also planar in geometry implying that the electrons may only be detected over a narrow out-of-plane angular range, typically less than ±2.5°.
One object of the present invention is therefore to address at least one of the problems of the prior art and/or to provide a choice that is useful in the art.